feature/book-page (#4)

Co-authored-by: Tim Rijkse <trijkse@gmail.com>
Reviewed-on: #4

js/store/cart.js

@@ -0,0 +1,158 @@
+/**
+ * Cart Store
+ * Manages shopping cart state with localStorage persistence
+ * Dispatches 'cart-updated' events when cart changes
+ */
+
+const CART_STORAGE_KEY = "milinda-cart";
+
+class CartStore {
+  constructor() {
+    this.items = this.loadFromStorage();
+  }
+
+  /**
+   * Load cart from localStorage
+   */
+  loadFromStorage() {
+    try {
+      const stored = localStorage.getItem(CART_STORAGE_KEY);
+      return stored ? JSON.parse(stored) : [];
+    } catch (e) {
+      console.error("Failed to load cart from storage:", e);
+      return [];
+    }
+  }
+
+  /**
+   * Save cart to localStorage
+   */
+  saveToStorage() {
+    try {
+      localStorage.setItem(CART_STORAGE_KEY, JSON.stringify(this.items));
+    } catch (e) {
+      console.error("Failed to save cart to storage:", e);
+    }
+  }
+
+  /**
+   * Dispatch cart-updated event
+   */
+  notifyUpdate() {
+    window.dispatchEvent(
+      new CustomEvent("cart-updated", {
+        detail: {
+          items: this.items,
+          count: this.getItemCount(),
+          total: this.getTotal(),
+        },
+      })
+    );
+  }
+
+  /**
+   * Add item to cart
+   * @param {Object} item - Item to add { title, author, price, type, image }
+   */
+  addItem(item) {
+    // Check if item already exists (by title and type)
+    const existingIndex = this.items.findIndex(
+      (i) => i.title === item.title && i.type === item.type
+    );
+
+    if (existingIndex >= 0) {
+      // Increment quantity
+      this.items[existingIndex].quantity += 1;
+    } else {
+      // Add new item
+      this.items.push({
+        ...item,
+        quantity: 1,
+        addedAt: Date.now(),
+      });
+    }
+
+    this.saveToStorage();
+    this.notifyUpdate();
+
+    return this.items;
+  }
+
+  /**
+   * Remove item from cart
+   * @param {number} index - Index of item to remove
+   */
+  removeItem(index) {
+    if (index >= 0 && index < this.items.length) {
+      this.items.splice(index, 1);
+      this.saveToStorage();
+      this.notifyUpdate();
+    }
+    return this.items;
+  }
+
+  /**
+   * Update item quantity
+   * @param {number} index - Index of item
+   * @param {number} quantity - New quantity
+   */
+  updateQuantity(index, quantity) {
+    if (index >= 0 && index < this.items.length) {
+      if (quantity <= 0) {
+        this.removeItem(index);
+      } else {
+        this.items[index].quantity = quantity;
+        this.saveToStorage();
+        this.notifyUpdate();
+      }
+    }
+    return this.items;
+  }
+
+  /**
+   * Clear all items from cart
+   */
+  clear() {
+    this.items = [];
+    this.saveToStorage();
+    this.notifyUpdate();
+    return this.items;
+  }
+
+  /**
+   * Get all items
+   */
+  getItems() {
+    return this.items;
+  }
+
+  /**
+   * Get total item count (sum of quantities)
+   */
+  getItemCount() {
+    return this.items.reduce((sum, item) => sum + item.quantity, 0);
+  }
+
+  /**
+   * Get cart total price
+   */
+  getTotal() {
+    return this.items.reduce((sum, item) => {
+      // Parse price like "€ 24,95" to number
+      const priceStr = item.price || "0";
+      const price = parseFloat(
+        priceStr.replace(/[€$£\s]/g, "").replace(",", ".")
+      );
+      return sum + price * item.quantity;
+    }, 0);
+  }
+}
+
+// Create singleton instance
+const cart = new CartStore();
+
+// Export for module use
+export default cart;
+
+// Also attach to window for global access
+window.cartStore = cart;